character or (shift-) key to be interpreted as modifying the value of the character (or key) following it in a string (or produced simultaneously in typing), either by prefixing a special character (" ^X-Q terminates the program"), or by interpreting it literally, thus escaping the default special interpretation of the following character.

special characters that are neither letters nor numbers but have special meaning either to the shell or the operating system, e.g., and , which perform redirection, and |, which "pipes" commands. For a metacharacter to be interpreted literally and not for its special meaning, it must be placed in quotation marks, e.g., `'.

A special character that is replaced by matching character strings when interpreted by the shell. Metacharacters, which define the form of a string, and literal characters, which match only themselves, make up regular expression

A character that is interpreted by UNIX shells and Wisconsin Package programs in a defined manner. The most common examples of metacharacters are the wildcards * and ?. The * wildcard metacharacter is interpreted to mean "any character or no character" and the ? wildcard metacharacter is interpreted to mean "any one character." For example, in the command % ls *.seq, the *.seq is interpreted as any filename ending with the extension ".seq". In the example % ls hsp?.seq, the hsp?.seq is interpreted as the name of any file beginning with "hsp" followed by one alphanumeric character, and ending with ".seq". You can use wildcard metacharacters to specify databases or divisions of databases within the Wisconsin Package. For example, GenEMBL:* specifies all of the entries in the GenEMBL database; Ba:* specifies all of the bacterial entries in GenEMBL; and Sw:hsp* specifies all of the sequences in SWISS-PROT that begin with "hsp". For more information, see "UNIX Metacharacter Differences" in Appendix D, Command and Keystroke Differences Between OpenVMS and UNIX.